package manifest

import (
	"encoding/json"
	"os"
	"sync"
)

type fileLogWriter struct {
	mu sync.Mutex
	f  *os.File
}

func NewFileLogWriter(path string) (LogWriter, error) {
	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
	if err != nil {
		return nil, err
	}
	return &fileLogWriter{f: f}, nil
}

func (w *fileLogWriter) Log(e LogEntry) {
	data, _ := json.Marshal(e)
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.f != nil {
		w.f.Write(data)
		w.f.Write([]byte("\n"))
	}
}

func (w *fileLogWriter) Close() {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.f != nil {
		w.f.Close()
		w.f = nil
	}
}